The present invention relates to a filter system for coupling to a dental handpiece. Bio film-derived dental unit waterline contamination is an emerging concern in the dental industry. Accumulated scientific evidence suggests that the potential exposure of dental personnel and patients to high concentrations of microbes may present a risk of infection. Although there is no current epidemiologic evidence of a public health threat, human pathogens including Pseudomonas, Legionella, and nontuberculous Mycobacterium species have been isolated within dental water lines. When a patient is immunologically suppressed, there is a potential risk of contracting serious illness upon being exposed to these human pathogens.
The Center for Disease Control (CDC) has recognized the importance of using sterile irrigation water for surgical procedures. The American Dental Association (ADA) has further recommended that by the year 2000, water for nonsurgical procedures should contain no more than 200 colony forming units (cfu) per millimeter of aerobic, mesophilic, heterotrophic bacteria in the output of a dental air-water syringe or handpiece. While the use of sterile water sources and flushing and purging of waterlines assists in reducing bacterial count in the output of a dental air-water syringe, the use of filters, particularly those having a pore size in the range of 0.22 millimicrons will enhance reduction of bacterial count. See The Journal of American Dental Association, Vol. 128, September 1997, article titled "COMPARISON OF DENTAL WATER QUALITY MANAGEMENT PROCEDURES".
At present, a simple, inexpensive, low maintenance solution to the problem of biofilm accumulation does not exist.
In studies comparing bacteria accumulation on polyethylene tubing as compared to inert glass surfaces, it was found that after 33 days in which flowing drinking water passed therethrough, there was 55 times more bacteria on the polyethylene tubing than on the inert glass surfaces. Small bore plastic tubing has been used in the field of dentistry for many years and such tubing is particularly susceptible to accumulation of biofilm containing human pathogens. Scientific literature suggests that virtually all dental units connected to public water supplies, where the dental units have not been treated or are not using point of use filtration systems, will generally far exceed 200 colony forming units per millimeter of aerobic, mesophilic, heterotrophic bacteria, the limit as recommended by the ADA and CDC guidelines for water quality.
In that it has been recommended that all major manufacturers of dental equipment be in compliance with ADA and CDC guidelines by the year 2000, a need has developed for an actual point of use filter system for dental handpieces that will facilitate such compliance.
Dental manufacturers of new equipment have built-in flushing and purging systems that rely upon bottled, sterile water and bacteriocidal cleaning agents. Such equipment can cost as much as $15,000.00 per room and maintenance employed in using these flushing and purging systems can take as long as 30 minutes per day. While the new equipment solves the compliance problem, it is expensive to purchase and time-consuming to operate. It also poses the risk of accidental spraying of disinfectant agents into the patient's mouth if not properly maintained.
Some manufacturers have developed in-line filters that are installed in the water supply line upstream of the handpiece connector or the connector to the dental handpiece. Manufacturers recommend that these filters be changed daily and, at the current cost of $2.00 per filter-line, the expense builds up over time while the dentist must ensure that daily changing of the filter has been carried out. Additionally, the short length of tubing that is provided to interpose the filter in the water system may become contaminated with biofilm. Such a retro-fit solution is illustrated in FIG. 2 that shows the waterline 8 with the in-line filter system 9 retro-fit therein.
As such, a need has developed for a system that may be employed inexpensively and easily to purify the water entering dental units so that a dentist will be encouraged to purchase and use such a system. It is with these needs in mind that the present invention was developed.